def __init__(self, parent=None, image=None, scale=1.0, horizontal_position=0.5, vertical_position=0.5):
def configure(self, image=None, scale=1.0, horizontal_position=0.5, vertical_position=0.5):
def zoom_out(self):
def zoom_in(self):

if __name__ == '__main__':
    app = QtGui.QApplication(sys.argv)
    win = ImageViewer(None, 'lenna.jpg')
    win.resize(480, 400)
    win.show()
    sys.exit(app.exec_())